Magnetic core



Nov. 25, 1930. P. TRMBETT MAGNETIC coRE Filed Nov. 26, m29

Inventor: Pflo Trombefla, w b9 MM Patented Nov. 25, 1930 UNITED STATESPATENT OFFICE PANFILO TROMBETTA, OF MILWAUKEE, WISCONSIN, ASSIGNOR TOGENERAL ELECTRIC A COMPANY, A CORPORATION F NEW YORK MAGNETIC GOREApplication filed November 26, 1929.- Serial No. 409,971.

My invention relates to construction of cores for alternating currentapparatus, particularly to the construction of cores for solenoids,magnets, transformers, reactors and the like made up of a plurality oflaminations.

In the present cores built up of laminations it is diliicult,particularly in the case of high silicon steel, to rivet a thick stackof l0 laminations tightly.

Loosely riveted laminations, the result of thick stacks, have theobjection of humming and this defeats the construction of quietlaminated solenoids and magnets.

Further, due to the fact that the rivets of necessity extend clearthrough all the laminations, the thicker the stack of laminations, thehigher is the induced voltage in the rivets.

It is an object of my invention to produce a thick stack of laminationsand to have such stacks consisting of tightly bound laminations.

It is a further object of my invention to reduce the length of themajority of the rivets by my particular construction, thus reducing theinduced voltage in the rivets 'of thick stacks.

A further object of my invention is the provision of a thick stack inwhich noise and humming is eliminated.

My invention will be better understood from the following descriptionwhen considered in connection with the accompanying 5 drawing and itsscope will be pointed out in the appended claims.

In the accompanying drawing, Fig. l represents a magnetic core embodyingmy'invention. Fig. 2 represents a section taken along 40 the line of 2 2of Fig. l showing the peculiar construction embodied in my invention.

In thepreferred embodiment of my invention, separate sections of a giventhickness of laminations are riveted togetherA to make thin stacksnecessitating the use of only short rivets. These sections are thenriveted together by means of longer rivets to form the u tightly rivetedtogether. This simple construction results in a very effective finishedproduct.

Referring specically to the drawings, Fig. l shows a core made up of aplurality of laminations designated by the numeral l. The method ofbuilding up the stack is shown more clearly in Fig. 2 which will bediscussed later. The laminations are then clamped between two thickerlaminations of the same 6U shape designated by the numerals 2 and 3.`The rivets 4., 5 and 6 bind the sections togiether to form the finishedstack as shown in Referring to Fig. 2, it will be seen that the 55rivets such as 4 and 6 do not extend clear through the entire stack oflaminations. These rivets are short and clamp together only a few of thelaminations. This, of course, results in a tightly clamped section. Ifdesired, each section could have clamped thicker laminations on theoutside thereof. After these sections have been assembled the sectionsare placed onev upon the other to form a core of a desired thickness.These sections are then clamped together by means of the upper and thelower plates 3 and 4 and the long rivets such as 5.

It will thus be seen that in the construction disclosed in my invention,the core will be E" made up of a number of tightly clamped togetherlaminations. This construction eliminates humming and noise as well asreduces the induced voltage in the rivets.

The embodiment of the invention illus- 35 trated and described hereinhas been selected for the purpose of clearly setting forth theprinciples involved. It Will be apparent, however, that the invention issusceptible of being modified to meet different conditions encounteredin its use and I, therefore, aim to cover by therappended claims allmodifications Vwithin the true spirit and 4scope of my invention.

What I claim as new and desire to secure 90 by Letters Patent of theUnited States is:

l'. A magnetic core comprisingV a stack of laminations, means fortightly fastening said laminations into separate groups to preventhumming of the laminations in each group' 100 and means for tightlyfastening said groups together to prevent humming of the stack;

2. A tightly riveted magnetic core for electrical apparatus comprising astack of lm- 5 inations, rivets for tightly fastening the laminationsinto separate groups to prevent humming and separate means for clampingthe eparate groups together to form a Sin'gle stac Y 'm 3. A magneticcore comprising a number of groups of laminations, rivets for tightlyriveting said laminations together into a group said groups placedtogether to form a single stack, and a thick lamination on each side ofthe stack between which said groups are tightly clamped to form a tightlaminated core.

In Witness whereof, I have hereunto set my hand this 23rd day ofNovember, 1929. 26 PANFILO TROMBETTA.

